Method of high sensitivity luminescence analysis

ABSTRACT

This invention relates to a method of high sensitivity luminescence analysis using, as an enhancer, 2-hydroxy-9-fluorenone, the compound expressed by the following formula ##STR1## or an oxazole compound expressed by the formula ##STR2## in the formula R 1  representing hydrogen, C n  H 2n+1  (here, n representing a positive integer of 1 to 4), XC n  H 2n  (here, X representing F, Cl, Br or I, and n representing a positive integer of 1 to 4), C n  H 2n+1  CO 2  (n being as defined above), a phenyl group, a naphthyl group, C n  H 2n+1  C 6  H 4  (n being as defined above), YC 6  H 4  (Y representing F, Cl, Br, I or a phenyl group) or XYC 6  H 3  (X and Y being as defined above).

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to a method of high sensitivity analysis through chemiluminescence measurement in use of enzymatic reactions, antigen-antibody reactions and nucleic acid hybridization in the areas of clinical laboratory testing, food inspection, environmental analysis, inspection of animals and plants, and manufacturing process control checking.

2. Background Art

The luminescent reaction using oxidation of luminol, isoluminol or a derivative thereof [abbreviated as chemiluminescent DPD (2,3-dihydro-1,4-phthalazinedione) in the following] by a peroxidase is used for immunoassay, analysis of elastase, analysis of glucose and analysis of oxidants. It is known that for improving the luminescent intensity of said luminescent reaction, it is effective to add an enhancer, such as those shown below, to the reaction system.

(1) 6-Hydroxybenzothiazole (Patent Publication No. SHO 56-5000252)

(2) A certain kind of phenol having a substitution group (Patent Publication No. SHO 59-171839)

(3) A certain kind of aromatic amine (Patent Publication No. SHO 61-54453)

However, such enhancers have the following difficulties.

The enhancer (1) is generally of lower luminescence intensity and smaller signal-to-background ratio.

The typical enhancer of the class (2) is p-iodophenol. Its luminescent signal is high, but the background is also high, therefore the signal-to-background ratio is relatively low.

In the case of the typical enhancer of the class (3) or N,N,N',N'-tetramethylbenzidine, the rise to the luminescent peak is slow, and much time is required for measurement.

For the reaction mechanism of the enhancer effect, there are reports proposing the requirement of efficient formation of luminol semiquinone radical [Thorpe, G. H. C. and Kricka, L. J., "Bioluminescence and Chemiluminescence: New Perspectives," Scholmerich, J., Andreesn, R., Kapp, A., Ernst, M. and Woods, W. G. (Eds), John Wiley, Chichester, pp. 199-208 (1987)] and the requirement of efficient formation of phenoxy radical [Hodgson, M. and Jones, P., Journal of Bioluminescence and Chemiluminescence, Vol. 3, pp. 21-25 (1989)].

However, the phenol derivatives include a number of compounds which do not show an enhancer effect, and it is difficult to choose an effective enhancer based upon the foregoing theories.

Also, for detection or quantification of a gene in a virulent microorganism, a prostaglandin or any other physiologically active substance, luteinizing hormone (LH) and other anterior pituitary hormones, and cytokines such as interleukin in blood, it is required to make a determination based on very small amount in body fluid. Thus, a high sensitivity detection system was called for, and for improvement of the detection sensitivity, an enhancer of higher efficiency has been desired.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method of high sensitivity luminescent analysis which is characteristically carried out in the presence of a novel enhancer.

Another object of the present invention is to provide a novel oxazole derivative which is effective as an enhancer and allows the luminescent analysis to be carried out with an enhancer of higher efficiency than the conventional enhancers used.

In detecting or determining a substance in use of the chemiluminescence produced through reaction of (a) a peroxidase or a derivative thereof, (b) an oxidant and (c) luminol or isoluminol, or a derivative thereof, the present invention relates to a method of high sensitivity luminescent analysis characterized in that the luminescence inducing reaction is carried out in the presence of at least one compound chosen from the group comprised of 2-hydroxy-9-fluorenone, the compound expressed by the following formula ##STR3## and oxazole derivatives expressed by the formula ##STR4## in the formula, R₁ representing hydrogen, C_(n) H_(2n+1) (here, n representing a positive integer of 1 to 4), XC_(n) H_(2n) (here, X representing F, Cl, Br or I; n being as defined in the foregoing), C_(n) H_(2n+1) CO₂ (n being as defined in the foregoing), phenyl group, naphthyl group, C_(n) H_(2n+1) C₆ H₄ (n being as defined in the foregoing), YC₆ H₄ (Y representing F, Cl, Br, I or phenyl group), or XYC₆ H₃ (X and Y being as defined in the foregoing).

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1 and 2 show the results of analysis of CA15-3 with an enhancer of the present invention, or 2-hydroxy- 9-fluorenone, compared against those with the conventional enhancers used, FIG. 1 showing the SN ratios of luminescent intensity after 5 seconds and FIG. 2 showing those after 10 seconds.

FIG. 3 shows the results of analysis of CA15-3 with and without addition of the enhancer of the invention to the luminescent system.

FIG. 4 is an IR spectrum of 2-chloromethyl-6-hydroxybenzoxazole obtained in Example 19, and FIG. 5 is an NMR spectrum of the same.

FIG. 6 is an IR spectrum of 2-ethoxycarbonyl-6-hydroxybenzoxazole obtained in Example 20, and FIG. 7 is an NMR spectrum of the same.

FIG. 8 is an IR spectrum of 2-(3-bromophenyl)-6-hydroxybenzoxazole obtained in Example 21, and FIG. 9 is an NMR spectrum of the same.

FIG. 10 is an IR spectrum of 2-(2-methylphenyl)hydroxybenzoxazole obtained in Example 22, and FIG. 11 is an NMR spectrum of the same.

FIG. 12 is an IR spectrum of 2-(3-chlorophenyl)-6-hydroxybenzoxazole obtained in Example 35, and FIG. 13 is an NMR spectrum of the same.

FIG. 14 is an IR spectrum of 2-(4-chlorophenyl)-6-hydroxybenzoxazole obtained in Example 36, and FIG. 15 is an NMR spectrum of the same.

FIG. 16 is an IR spectrum of 2-(2-naphthyl)-6-hydroxybenzoxazole obtained in Example 37, and FIG. 17 is an NMR spectrum of the same.

FIG. 18 is an IR spectrum of 2-(2,4-dichlorophenyl)-6-hydroxybenzoxazole obtained in Example 38, and FIG. 19 is an NMR spectrum of the same.

FIG. 20 shows the values of SN ratio obtained in Example 51 and Reference 22.

DETAILED DESCRIPTION OF THE INVENTION

The chemiluminescence enhancing effect of the enhancer of the present invention, or 2-hydroxy-9-fluorenone, ##STR5## 4-hydroxy-3-[3-(4-hydroxyphenyl)-1-oxo-2-propenyl]-2H-1-benzopyrane-2-one (abbreviated as HHBP in the following) or an oxazole derivative expressed by formula [I] can be confirmed as the luminescent signal-to-background ratio obtainable in the peroxidase/oxidant/chemiluminescent DPD system is greatly improved when the enhancer of the present invention is added to the system. The term "background" used here refers to the luminescent intensity in the absence of the peroxidase or derivative thereof.

The peroxidase used according to the present invention is not particularly limited but is preferably a plant peroxidase such as horse radish peroxidase. For the peroxidase derivative, there may be listed, for example, a peroxidase-antibody conjugate, peroxidase-antigen conjugate, peroxidase-streptoavidin conjugate and biotin bonded peroxidase. The antibody used here is not particularly limited, but there may be preferably used such partial structures as Fab' and F(ab)₂ in addition to intact IgG and IgM. The antigen is also not limited, and low molecular haptens such as fluorescein and steroid hormone and high molecular substances such as polypeptides, proteins and polysaccharides are also usable.

For the nucleic acid hybridization, linear and cyclic DNA and RNA of 10 or more bases are usable.

As an oxidant, hydrogen peroxide is preferably used, but perborates and hypochlorites are also usable.

The chemiluminescent DPD used according to the present invention includes luminol, isoluminol and N-(4-aminobutyl)-N-ethylisoluminol, and antigens, antibodies and nucleic acids bonded thereto. Of these, luminol is particularly preferable.

HHBP used as an enhancer according to the present invention can be produced through condensation of 3-acetyl-4-hydroxycumarin and para-hydroxybenbenzoaldehyde in the presence of an amine, according to the method described in the patent publication No. Sho 50-46666.

As described in the foregoing, the present invention relates to a method of high sensitivity luminescent analysis which is characteristically carried out in the presence of an oxazole derivative expressed by the formula ##STR6## in the formula, R₁ representing hydrogen C_(n) H_(2n+1) (here, n representing a positive integer of 1 to 4), XC_(n) H_(2n) (here, X representing F, Cl, Br or I, and n being as defined above), C_(n) H_(2n+1) CO₂ (n being as defined above), C_(n) H_(2n+1) C₆ H₄ (n being as defined above), phenyl group, naphthyl group, YC₆ H₄ (Y representing F, Cl, Br, or a phenyl group) or XYC₆ H₃ (X and Y being as defined above).

Specifically, for R₁ in the compound [I] of the present invention, there may be listed hydrogen and, as alkyl group of the carbon atom number of 1 to 4, such groups as methyl, ethyl, propyl (n- and iso-), butyl (n-, iso-, sec- and tert-) and phenyl.

Also, for the halogenated alkyl group, there may be listed such groups as fluoromethyl, 1-chloromethyl, bromomethyl, iodomethyl, 1-fluoroethyl, 2-fluoroethyl, 1-chloroethyl, 2-chloroethyl, 1-bromoethyl, 2-bromoethyl, 1-iodoethyl, 2-iodoethyl, 1-fluoropropyl, 2-fluoropropyl, 3-fluoropropyl, 1-fluoro-1-methylethyl, 2-fluoro-1-methylethyl, 1-chloropropyl, 2-chloropropyl, 3-chloropropyl, 1-chloro-1-methylethyl, 2-chloro-1-methylethyl, 1-bromopropyl, 2-bromopropyl, 3-bromopropyl, 1-bromo-1-methylethyl, 2-bromo-1-methylethyl, 1-iodopropyl, 2-iodopropyl, 3-iodopropyl, 1-iodo-1-methylethyl, 2-iodo-1-methylethyl, 1-fluoropropyl, 2-fluorobutyl, 3-fluorobutyl, 4-fluorobutyl, 1-fluoro-1-methylpropyl, 2-fluoro-1-methylpropyl, 3-fluoro-1-methylpropyl, 1-fluoromethylpropyl, 1-fluoro-2-methylpropyl, 2-fluoro-2-methylpropyl, 3-fluoro-2-methylpropyl, 1-fluoromethyl-1,1-dimethylmethyl, 1-chlorobutyl, 2-chlorobutyl, 3-chlorobutyl, 4-chlorobutyl, 1-chloro-1-methylpropyl, 2-chloro-1-methylpropyl, 3-chloro-1-methylpropyl, 1-chloromethylpropyl, 1-chloro-2-methylpropyl, 2-chloro-2-methylpropyl, 3-chloro-2-methylpropyl, 1 -chloromethyl-1,1-dimethylmethyl, 1-bromobutyl, 2-bromobutyl, 3-bromobutyl, 4-bromobutyl, 1-bromo-1-methylpropyl, 2-bromo-1-methylpropyl, 3-bromo-1-methylpropyl, 1-bromomethylpropyl, 1-bromo-2-methylpropyl, 2-bromo-2-methylpropyl, 3-bromo-2-methylpropyl, 1-bromomethylmethyl-1,1-dimethylmethyl, 1-iodobutyl, 2-iodobutyl, 3-iodobutyl, 4-iodobutyl, 1-iodo-1-methylpropyl, 2-iodo- 1-methylpropyl, 3-iodo-1-methylpropy, 1-iodo-2-methylpropyl, 2-iodo-2-methylpropyl, 3-iodo-2-methylpropyl and 1-iodomethyl-1,1-dimethylmethyl.

For the alkoxycarbonyl group, there may be listed such groups as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, 1-methylethoxycarbonyl, butoxycarbonyl, 1-methylpropoxycarbonyl, 2-methylpropoxycarbonyl and 1,1-dimethylethoxycarbonyl.

For the alkyl substituted phenyl group, there may be listed such groups as 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 2-propylphenyl, 3-propylphenyl, 4-propylphenyl, 2-(1-methylethyl), 3-(1-methylethyl), 4-(1-methylethyl), 2-butylphenyl, 3-butylphenyl, 4-butylphenyl, 2-(1-methylpropyl)phenyl, 3-(1-methylpropyl)phenyl, 4-(1-methylpropyl)phenyl, 2-(2-methylpropyl)phenyl, 3-(2-methylpropyl)phenyl, 4-(2-methylpropyl)phenyl, 2-(1,1-dimethylethyl)phenyl, 3-(1,1-dimethylethyl)phenyl and 4-(1,1-dimethylethyl)phenyl.

For the halogen substituted phenyl group, there may be listed such groups as 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 2-bromophenyl, 3-bromophenyl, 4-bromophenyl, 2-iodophenyl, 3-iodophenyl and 4-iodophenyl.

For the disubstituted phenyl group, there may be listed such groups as 2,4-dichlorophenyl and 3,5-dichlorophenyl.

Of these, preferable substitution groups are hydrogen, methyl group, phenyl group, chloromethyl group, ethoxycarbonyl group, 2-methylphenyl group, 3-bromophenyl group, 4-chlorophenyl group and 2,4-dichlorophenyl group.

Of the compounds expressed by the formula [I], any oxazole derivative expressed by the formula ##STR7## in the formula, R₂ representing XC_(n) H_(2n) (here, X representing F, Cl, Br or I, and n representing a positive integer of 1 to 4), C_(n) H_(2n+1) CO₂ (n being as defined above), C_(n) H_(2n+1) C₆ H₄ (n being as defined above), naphthyl group, YC₆ H₄ (Y representing F, Cl, Br, or I or a phenyl group) XYC₆ H₃ (X and Y being as defined above), is a novel substance.

The compound [I] of the present invention can be produced by synthesis according to the reaction formula ##STR8## in the formula, R₁ representing hydrogen, C_(n) H_(2n+1) (here, n representing a positive integer of 1 to 4), XC_(n) H_(2n) (here, X representing F, Cl, Br or I, and n being as defined above), C_(n) H_(2n+1) CO₂ (n being as defined above), phenyl group, naphthyl group, C_(n) H_(2n+1) C₆ H₄ (n being as defined above), YC₆ H₄ (Y representing F, Cl, Br, I or a phenyl group) or XYC₆ H₃ (X and Y being as defined above); R₃ representing C_(n) H_(2n+1) (n being as defined above); and Z representing F, Cl, Br or I.

Here, R₁ used in the compound [III] is the same as R₁ used in the compound [I].

Also, for the alkyl group R₃, there may be listed such groups as methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl and 1,1-dimethylethyl.

The base used according to the present invention includes carbonates such as sodium hydrogencarbonate, potassium hydrogencarbonate, sodium carbonate and potassium carbonate, amines such as trimethylamine, triethylamine and t-butylamine, and aromatic heterocyclic compounds such as pyridine and quinoline, but sodium hydrogencarbonate is particularly preferable.

The reaction does not require a solvent and proceeds at a temperature of 20° to 150° C., but for enhancing the yield of the objective product, a temperature of 50° to 120° C. is preferable.

The oxazole compound [I] may also be produced, when R₁ is XC_(n) H_(2n) (X representing F, Cl, Br or I, and n representing a positive integer of 1 to 4), according to the formula (2), or when R₁ is YC₆ H₄ (Y representing F, Cl, Br, I or a phenyl group), according to the formula (3), set forth below. ##STR9## in the formula, R₃ representing C_(n) H_(2n+1) (n representing a positive integer of 1 to 4), and X and Z representing F, Cl, Br or I respectively.

For the halogenated alkyl group used in the compound [IV], the same halogenated alkyl group as that used in the compound [I] may be used. Also, for R₃ used in the compound [IV], the same R₃ as that used in the compound [III] may be used.

The reaction solvent used according to the present invention includes alcohols such as methanol, ethanol, propanol and butanol, ethers such as ethyl ether and THF, and aprotic polar solvents such as DMF and DMSO. Of these, ethanol is particularly preferable.

The reaction proceeds at a temperature of 20° to 150° C., but for increasing the yield of the objective product, a temperature of 60° to 90° C. is preferable. ##STR10## in the formula, Y representing F, Cl, Br, I or a phenyl group, and Z representing F, Cl, Br or I.

For the substituted phenyl group used in the compound [V], the halogenated phenyl group or phenylphenyl group used in the compound [I] may be used.

The first stage of the reaction does not require a solvent and proceeds at a temperature of 100° to 280° C., but for enhancing the yield of the compound [VI], a temperature of 150° to 250° C. is preferable.

The base used for hydrolytic reaction of the compound [VI] includes sodium hydroxide. potassium hydroxide and sodium carbonate, but sodium hydroxide is particularly preferable. For the solvent, water, alcohols such as methanol and ethanol and ethers such as THF are usable, but a mixture of water/ethanol is particularly preferable.

The hydrolytic reaction proceeds at a temperature of 20° to 50° C., but for enhancing the yield of the object, a temperature of 25° to 35° C. is preferable.

The enhancer of the present invention is usable for determination of a substance in use of a luminescent system comprising a peroxidase, chemiluminescent DPD and oxidant but is preferably usable for determination through enzymatic immunoassay and DNA hybridization.

The present invention will now be described in detail with reference to nonlimiting examples.

The reagents and apparatus used in the examples are as described below.

Reagents

4-Aminoresorcinol hydrochloride and chloroacetonitile were purchased from the Aldrich Co.; ethanol, DMSO, diethyl oxalate, 3-bromobenzoyl chloride, 2-methylbenzoyl chloride, 4-chlorobenzoyl chloride, 2,4-dichlorobenzoyl chloride, luminol (5-amino-2,3-dihydro-1,4-phthalazinedione and isoluminol (6-amino-2,3-dihydro-1,4-phthalazinedione) purchased from the Tokyo Kasei Co.; phosphorus pentachloride and sodium hydrogencarbonate purchased from the Kanto Kagaku Co.; hydrogen chloride cylinder purchased from the Tsurumi Soda Co.; N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and tris(hydroxymethyl)aminomethane purchased from the Sigma Chemical Co.; horse radish peroxidase (HRP) purchased from the Boehringer Mannheim GmbH; powder PBS purchased from the Nissui Seiyaku Co.; bovine serum albumin (BSA) purchased from the Seikagaku Kogyo Co.; and 2-hydroxy-9-fluorenone purchased from the Aldrich Chemical Co.

HHBP was prepared according to the method described in Patent Publication No. SHO 50-46666.

Mammary cancer related antigen (CA15-3) and anti-CA15-3 antibody (mouse monoclonal antibody) were provided by Centocor (Malvern, USA). The horse radish peroxidase labeled anti-CA15-3 antibody was prepared by the maleimide hinge method [Yoshitake, S. et al., J. Biochem., 92, 1413-1424 (1982)] and isolated and purified by Pharmacia's FPLC using a hydroxy-apatite column (Mitsui-Toatsu, HCA-column, φ7.6 mm×L100 mm).

Anti-CA15-3 antibody coated polystyrene beads were prepared by immersing 6 mm diameter polystyrene beads (Meiwa Fusso Shokai, surface roughness #80) in a 10 μg/ml PBS solution of anti-CA15-3 antibody overnight.

Analytical Apparatus

The chemiluminescent reaction was carried out in a disposable 3 ml plastic tube of 12 mmφ×47 mm. The generated light was detected by a luminometer (Biolumat LB9500T), a product of the Berthold Co.

The infrared spectrum (abbreviated as IR in the following) was measured by an FT/IR-5000, product of the Nippon Bunko Kogyo Co.

The nuclear magnetic resonance spectrum (abbreviated as NMR in the following) was measured by an EX90FTNMR, product of the Nippon Denshi Co.

The mass spectrum (abbreviated as MS in the following) was measured by the direct introduction method using a JMS D300 spectrograph. The high resolution MS was determined with a JMS DX-303 spectrograph.

EXAMPLE 1 Luminescent assay of peroxidase in use of luminol and 2-hydroxy-9-fluorenone

200 μl of luminol (100 mM DMSO solution 10 μl/10 ml 0.1 M tris-hydrochloride buffer solution, pH 7.5), 200 μl of 2-hydroxy-9-fluorenone (100 mM DMSO solution 10 μl/10 ml 0.1 M tris-hydrochloride buffer solution, pH 7.5), 10 μl of HRP [100,000 times dilution of 1111 unit/mg with a PBS buffer solution containing 1 g/1 of BSA (pH 7.4)], and 10 μl of hydrogen peroxide (1000 times dilution of a 9.1 M aqueous solution) were introduced into a plastic cuvette, and the mixture was stirred for 3 seconds with a vortex mixer, and the luminescent intensity after 10 seconds was measured. Next, 10 μl of a PBS buffer solution containing no HRP (pH 7.4) and the foregoing amounts of luminol, 2-hydroxy-9-fluorenone and hydrogen peroxide were mixed and stirred, and the luminescent intensity after 10 seconds was measured. The ratio of the former to the latter is shown as a signal-to-background ratio (SN ratio) in Table 1.

EXAMPLE 2

The procedure of Example 1 was repeated with isoluminol used in place of luminol. The result is shown in Table 1.

EXAMPLE 3

The procedure of Example 1 was repeated with N-(4-amino-butyl)-N-ethylisoluminol used in place of luminol. The result is shown in Table 1.

REFERENCES 1 TO 3

The procedures of Examples 1, 2 and 3 were followed except that 2-hydroxy-9-fluorenone was not used. The results are also shown in Table 1.

                  TABLE 1                                                          ______________________________________                                         Signal-to-background ratio (SN ratio) with                                     2,3-dihydro-1,4-phthalazinedione (DPD)                                                          Luminescent intensity after                                                    10 seconds (relative value)                                           DPD        +HRP    -HRP    SN ratio                                    ______________________________________                                         Example 1 Luminol      449863  103   4368                                      Example 2 Isoluminol    9885    99   99.8                                      Example 3 N-(4-aminobutyl)-                                                                            17370   96   180.9                                               N-ethylisoluminol                                                    Reference 1                                                                              Luminol        149   133   1.12                                      Reference 2                                                                              Isoluminol     167   154   1.08                                      Reference 3                                                                              N-(4-aminobutyl)-                                                                             157   137   1.15                                                N-ethylisoluminol                                                    ______________________________________                                    

EXAMPLE 4 Luminescent assay of CA15-3 antigen with 2-hydroxy-9-fluorenone and various enhancers used

Diluting a CA15-3 antigen solution (615 U/ml) with a phosphate buffer solution (PBS) containing bovine serum albumin into solutions of the concentrations of 300 U/ml, 200 U/ml, 100 U/ml, 50 U/ml, 25 U/ml and 0 U/ml (PBS containing bovine serum albumin), these were taken as standard CA15-3 solutions.

Two samples of each of the standard CA15-3 solutions of the foregoing concentrations were poured into the wells of a tray (25 wells), each in 20 μl. Then, 300 μl of a peroxidase labeled anti-CA15-3 antibody (mouse) was added to the respective wells. To each well, an antibody coated bead having the adhering liquid soaked up with filter paper was added with a pincette.

Applying a tray cover seal, the tray was lightly tapped for admixture of the components in the respective wells, and each mixture was allowed to react at 25° C. for 2 hours. After completion of the reaction, the beads were washed 3 times, each time with 5 ml of physiological saline, with a bead washer used. After washing, each bead in the tray was transferred to a test tube then to a plastic cuvette for measurement with a luminometer.

200 μl of luminol solution (100 mM DMSO solution 10 μl/10 ml 0.1 M tris-hydrochloride buffer solution, pH 7.5), 200 μl of 2-hydroxy-9-fluorenone solution (100 mM DMSO solution 10 μl/10 ml 0.1 M tris-hydrochloride buffer solution, pH 7.5) and 10 μl of hydrogen peroxide solution (1000 times dilution of a 9.1 M aqueous solution) were added to each plastic cuvette, and the luminescent intensities after 5 and 10 seconds were measured. The results are shown in Tables 2-1 and 2-2.

The ratios of the luminescent intensities after 5 and 10 seconds of the standard CA15-3 antigen solutions (300 U/ml, 200 U/ml, 100 U/ml, 50 U/ml and 25 U/ml) to those after 5 and 10 seconds of 0 U/ml (SN ratios) were obtained, as shown in FIGS. 1 and 2.

REFERENCES 4 TO 8

The procedure of Example 4 was followed with p-iodophenol, p-hydroxycinnamic acid, p-phenylphenol, 6-hydroxybenzothiazole and N,N,N',N'-tetramethylbenzidine used in place of 2-hydroxy-9-fluorenone. The luminescent intensities are shown in Tables 2-1 and 2-2, and the SN ratios shown in FIGS. 1 and 2.

                                      TABLE 2-1                                    __________________________________________________________________________     Luminescent intensities after 5 seconds with various                           enhancers added (relative values)                                                                     CA15-3 (U/ml)                                                  Enhancers       0   25  50  100 200 300                                 __________________________________________________________________________     Reference 4                                                                           p-Iodophenol    1686                                                                               10314                                                                              28463                                                                              67438                                                                              142810                                                                             238017                              Reference 5                                                                           p-Hydroxycinnamic acid                                                                         1745                                                                               4661                                                                               7736                                                                               10314                                                                              17851                                                                              28246                               Reference 6                                                                           p-Phenylphenol  590 7023                                                                               10525                                                                              21541                                                                              31672                                                                              49180                               Reference 7                                                                           6-Hydroxybenzothiazole                                                                         912 3471                                                                               6843                                                                                9719                                                                              15868                                                                              22810                               Reference 8                                                                           N,N,N',N'-tetramethylbenzidine                                                                 203  99  174                                                                                298                                                                                1785                                                                               3968                               Example 4                                                                             2-Hydroxy-9-fluorenone                                                                         472 13554                                                                              24492                                                                              41803                                                                              64033                                                                              116066                              __________________________________________________________________________

                                      TABLE 2-2                                    __________________________________________________________________________     Luminescent intensities after 10 seconds with various enhancers added          (relative values)                                                                                     CA15-3 (U/ml)                                                  Enhancers       0   25  50  100 200 300                                 __________________________________________________________________________     Reference 4                                                                           p-Iodophenol    1796                                                                               12664                                                                              38123                                                                              85089                                                                              153034                                                                             242580                              Reference 5                                                                           p-Hydroxycinnamic acid                                                                         1630                                                                               4670                                                                               7663                                                                               10363                                                                              15525                                                                              27940                               Reference 6                                                                           p-Phenylphenol  675 7003                                                                               10487                                                                              21288                                                                              35650                                                                              52421                               Reference 7                                                                           6-Hydroxybenzothiazole                                                                         811 3438                                                                               6819                                                                                9696                                                                              18092                                                                              22644                               Reference 8                                                                           N,N,N',N'-tetramethylbenzidine                                                                 423  84  354                                                                                290                                                                                3127                                                                               6900                               Example 4                                                                             2-Hydroxy-9-fluorenone                                                                         643 13652                                                                              24248                                                                              40907                                                                              63885                                                                              116905                              __________________________________________________________________________

EXAMPLE 5 Luminescent assay of peroxidase in use of luminol and HHBP

200 μl of luminol solution (100 mM DMSO solution 10 μl/10 ml 0.1 M tris-hydrochloride buffer solution, pH 8.5), 200 μl of HHBP solution (100 mM DMSO solution 10 μl/10 ml 0.1 M tris-hydrochloride buffer solution, pH 8.5), 10 μl of horse radish peroxidase (HRP) solution (100,000 times dilution of 1111 unit/mg with a PBS buffer solution (pH 7.0) containing 1 g/l of BSA) and 10 μl of hydrogen peroxide solution (1000 times dilution of a 9.1 M aqueous solution) were introduced into a plastic tube and stirred for 3 seconds with a vortex mixer, then the luminescent intensity after 1 minute was measured.

Next, 10 μl of the buffer solution (pH 7.0) not containing HRP and the foregoing amounts of luminol, HHBP and hydrogen peroxide solution were mixed and stirred, and the luminescent intensity after 1 minute was measured. The ratio of the former to the latter is shown as signal-to-background ratio (SN ratio) in Table 3.

EXAMPLES 6 AND 7

As Examples 6 and 7, the luminescent intensities were measured similarly to Example 5 except that isoluminol (Example 6) and ABEI (Example 7) were used in place of luminol in Example 5, as shown in Table 3.

REFERENCES 9 TO 11

Luminescent intensities were measured similarly to Examples 5 to 7 except that HHBP was not used, as shown in Table 3.

From Examples 5 to 7 and References 9 to 11, it has become apparent that the method of the invention is a distinguished method of luminescence analysis.

                  TABLE 3                                                          ______________________________________                                         Signal-to-background ratios (SN ratios) with                                   2,3-dihydro-1,4-phthalazinedione (DPD)                                                        Luminescent intensity after                                                    1 minute (relative value)                                               DPD      +HRP     -HRP     SN ratio                                    ______________________________________                                         Example 5 Luminol    453039   88     5148                                      Example 6 Isoluminol  7524    24     313.5                                     Example 7 ABEI        21073   31     679.8                                     Reference 9                                                                              Luminol      550    507    1.08                                      Reference 10                                                                             Isoluminol   160    137    1.17                                      Reference 11                                                                             ABEI         188    180    1.04                                      ______________________________________                                    

EXAMPLE 8 Synthesis of 6-hydroxybenzoxazole

2.0 g of 4-aminoresorcinol hydrochloride (12.4 mmol), 8.5 ml of methyl orthoformate (51.4 mmol) and 1.07 g of sodium hydrogencarbonate (12.8 mmol) were introduced into a two-necked flask provided with a cooling condenser, and the mixture was stirred in argon atmosphere at 100° C. for a whole day and night. After completion of the reaction, the reaction solution was cooled. Then, hexane was added, and the reaction product was filtered. The crystal was washed with water to remove the inorganic salt then filtered again.

The obtained crystal was dissolved in acetone, and with activated carbon added, the solution was refluxed with heat for 1.5 hours. Removing the activated carbon, and evaporating acetone the obtained crystal was recrystallized with acetone-water. There was obtained 0.28 g of a white powder. The reaction yield was 16.7%.

m.p.: 183.5° to 185.2° C.

IR (KBr, cm⁻¹): 3150, 1630, 1528, 1489, 1276, 1236, 1195, 1104, 1085, 816

NMR (δ, DMSO-d₆) 6.81 (dd, 1H), 7.03 (d, 1H), 7.53 (d, 1H), 8.46 (s, 1H), 9.75 (s, 1H)

MS (EI): 135 (M⁺), 52, 31

High resolution MS (EI): C₇ H₅ O₂ N: Calclulated: 135.0344. Observed 135.0332.

Luminescent assay of peroxidase in use of luminol and 6-hydroxybenzoxazole

200 μl of a luminol solution (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution, pH 8.5), 200 μl of a 6-hydroxybenzoxazole solution (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution, pH 8.5), 10 μl of a horse radish peroxidase (HRP) solution (10,000 times dilution of 1111 unit/mg with a PBS buffer solution (pH 7.0) containing 1 g/l of BSA) and 10 μl of a hydrogen peroxide solution (1000 times dilution of a 9.1 M aqueous solution) were introduced into a plastic cuvette and stirred for 3 seconds with a vortex mixer used, then the luminescent intensity after 1 minute was measured.

Next, 10 μl of the buffer solution not containing HRP and the foregoing amounts of luminol, 6-hydroxybenzoxazole and hydrogen peroxide solution were mixed and stirred, and the luminescent intensity after 1 minute was measured. The ratio of the former to the latter is shown as signal-to-background ratio (SN ratio) in Table 4.

EXAMPLES 9 AND 10

As Examples 9 and 10, the luminescent intensities were measured similarly to Example 8 except that isoluminol (Example 9) and N-(4-aminobutyl)-N-ethylisoluminol (abbreviated as ABEI in the following) (Example 10) were used in place of luminol in the luminescent assay in Example 8, as shown in Table 4.

EXAMPLE 11

The luminescent intensity was measured similarly to Example 8 except that 2-methyl-6-hydroxybenzoxazole was used in place of 6-hydroxybenzoxazole in Example 8, as shown in Table 4.

EXAMPLES 12 AND 13

As Examples 12 and 13, the luminescent intensities were measured similarly to Example 11 except that isoluminol (Example 12) and ABEI (Example 13) were used in place of luminol in Example 11, as shown in Table 4.

EXAMPLE 14

The luminescent intensity was measured similarly to Example 8 with 2-phenyl-6-hydroxybenzoxazole used in place of 6-hydroxybenzoxazole in Example 8, as shown in Table 4.

EXAMPLES 15 AND 16

The luminescent intensities were measured similarly to Example 14 except that isoluminol (Example 15) and ABEI (Example 16) were used in place of luminol in Example 14, as shown in Table 4.

REFERENCES 12 TO 14

As References 12 to 14, the luminescent intensities were measured similarly to Examples 8 to 10 except that 6-hydroxybenzoxazole was not used, as shown in Table 4.

                                      TABLE 4                                      __________________________________________________________________________     Signal-to-background ratios through combination of enhancers                   and 2,3-dihydro-1,4-phthalazinedione (DPD)                                                                  Luminescent intensity after                                                    1 minute (relative value)                                Enhancer        DPD   +HRP  -HRP                                                                               SN ratio                                __________________________________________________________________________     Example 8                                                                             6-Hydroxybenzoxazole                                                                           Luminol                                                                              664522                                                                               81  8204.0                                  Example 9                                                                             6-Hydroxybenzoxazole                                                                           Isoluminol                                                                           10277 25  411.1                                   Example 10                                                                            6-Hydroxybenzoxazole                                                                           ABEI  26481 26  1018.5                                  Example 11                                                                            2-Methyl-6-hydroxybenzoxazole                                                                  Luminol                                                                              975682                                                                               78  12508.7                                 Example 12                                                                            2-Methyl-6-hydroxybenzoxazole                                                                  Isoluminol                                                                           15028 28  536.7                                   Example 13                                                                            2-Methyl-6-hydroxybenzoxazole                                                                  ABEI  46109 26  1773.4                                  Example 14                                                                            2-Phenyl-6-hydroxybenzoxazole                                                                  Luminol                                                                              2764970*                                                                             82  33719.1*                                Example 15                                                                            2-Phenyl-6-hydroxybenzoxazole                                                                  Isoluminol                                                                           54033 50  1080.7                                  Example 16                                                                            2-Phenyl-6-hydroxybenzoxazole                                                                  ABEI  92167 50  1843.3                                  Reference 12                                                                          None            Luminol                                                                               622  357 1.7                                     Reference 13                                                                          None            Isoluminol                                                                            459  193 2.4                                     Reference 14                                                                          None            ABEI   1371 226 6.1                                     __________________________________________________________________________      *Value measured with HRP diluted 10 times and the luminescent intensity        after 1 minute multiplied 10 times.                                      

EXAMPLE 17 Luminescent assay of CA15-3 antigen in use of HHBP

A CA15-3 antigen solution (615 U/ml) was diluted with a phosphate buffer solution (PBS) containing bovine serum albumine into solutions of the concentrations of 300 U/ml, 200 U/ml, 100 U/ml, 50 U/ml, 25 U/ml and 0 U/ml (PBS containing bovine serum albumine), and these were taken as standard CA15-3 solutions.

Two samples of each of the standard solutions of the foregoing concentrations were introduced into the wells of a tray (25 wells), each in 20 μl. To each well, 300 μl of a peroxidase labeled marker anti-CA15-3 antibody (mouse) was added. Then, an antibody coated bead having the adhering liquid soaked up with filter paper was added to each well.

Applying a tray cover seal and lightly tapping for mixing, the reaction was carried out at 25° C. for 2 hours. After completion of the reaction, the mixture was washed 3 times with 5 ml of physiological saline in a bead washer. After washing, each bead in the tray was transferred to a test tube then to a plastic tube for measurement with a luminometer.

Adding 200 μl of luminol solution (100 mM DMSO solution 10 μl/10 ml 0.1 M tris-hydrochloride buffer solution, pH 7.5), 200 μl of HHBP solution (100 mM DMSO solution 10 μl/ml 0.1 M tris-hydrochloride buffer solution, pH 7.5) and 10 μl of hydrogen peroxide solution (1000 times dilution of a 9.1 M aqueous solution) to the respective plastic tubes, the luminescent intensities after 10 seconds were measured. Mean luminescent intensities of two samples are shown in Table 5.

The ratios of the mean luminescent intensities after 10 seconds of the standard CA15-3 antigen solutions (300 U/ml, 200 U/ml, 100 U/ml, 50 U/ml and 25 U/ml) to the mean luminescent intensity after 10 seconds of 0 U/ml (SN ratios) were obtained, as shown in FIG. 3.

EXAMPLE 18 Luminescent assay of CA15-3 antigen in use of 2-methyl-6-hydroxybenzoxazole

Following the procedure of Example 17 except for the use of 2-methyl-6-hydroxybenzoxazole in place of HHBP in Example 17 the luminescent intensities were measured. The mean luminescent intensities are shown in Table 5, and the SN ratios shown in FIG. 3.

REFERENCE 15

Following the procedure of Example 17 except that HHBP and 2-methyl-6-hydroxybenzoxazole were not used, the measurement was made similarly. The mean luminescent intensities are shown in Table 5, and the SN ratios shown in FIG. 3.

                                      TABLE 5                                      __________________________________________________________________________     Analysis of CA15-3: Mean luminescent intensities                               after 10 seconds (relative values)                                                           CA15-3 (U/ml)                                                           Enhancer                                                                              0  25 50  100 200 300                                            __________________________________________________________________________     Example 17                                                                            HHBP   602                                                                               8031                                                                              17045                                                                              30454                                                                              65824                                                                              91745                                          Example 18                                                                            2-Methyl-6-                                                                           401                                                                               3370                                                                               6929                                                                              17223                                                                              27926                                                                              46613                                                 hydroxy-                                                                       benzoxazole                                                             Reference 15                                                                          None   154                                                                                148                                                                               165                                                                                165                                                                                152                                                                                182                                           __________________________________________________________________________

EXAMPLE 19 Synthesis of 2-chloromethyl-6-hydroxybenzoxazole

26.1 g (345.7 mmol) of chloroacetonitrile, 20 ml of absolute ethanol, and 70 ml of ether were introduced into a three-necked 300 ml flask provided with stirring vanes, and while stirring gently, hydrogen chloride gas was blown into the flask at room temperature for about 40 minutes. A white precipitate was produced which was then filtered and washed with ether. There was obtained 37.5 g (237.3 mmol) of ethyl chloromethylimidate hydrochloride. The yield of the reaction was 68.7%.

1.78 g (11.3 mmol) of said ethyl chloromethylimidate hydrochloride, 1.22 g (7.55 mmol) of 4-aminoresorcinol hydrochloride, and 20 ml of ethanol were introduced into a two-necked flask provided with a Dimroth condenser, and the mixture was refluxed with heat in argon atmosphere for a whole day and night. After completion of the reaction and cooling, the crystal was filtered and washed with hexane, then the object was vacuum dried. There was obtained 0.40 g (2.33 mmol) of 2-chloromethyl-6-hydroxybenzoxazole, and the yield of the reaction was 30.9%.

m.p.: 148.5° to 153.7° C.

IR (FIG. 4, KBr, cm⁻¹): 3076, 1615, 1572, 1491, 1334, 1238, 1141, 837

NMR (FIG. 5, DMSO-d₆) 4.97 (s, 2H), 6,84 (dd, 2H), 7.08 (d, 1H), 7.55 (d, 1H), 9.89 (s, 1H)

MS (EI): 183 (M ), 148

High resolution MS (EI): C₈ H₆ O₂ NCl: Calculated: 183.0015. Observed 183.0051.

EXAMPLE 20 Synthesis of 2-ethoxycarbonyl-6-hydroxybenzoxazole

61.3 g (420 mmol) of diethyl oxalate and 90.2 g (433 mmol) of phosphorous pentachloride were introduced into a three-necked 500 ml flask provided with stirring vanes and a cooling condenser and were stirred with heat at 105° C. for 17 hours.

The remaining liquid was vacuum distilled under 11 mmHg, and 53.2 g (265 mmol) of the fraction distilling at 77° to 85° C. were collected. The yield of dichloroethoxyethyl acetate was 63.0%.

85 ml of dehydrated ether, 35.5 ml of absolute ethanol and 53.2 g (265 mmol) of dichloroethoxyethyl acetate were introduced into a three-necked 500 ml flask provided with stirring vanes, a cooling condenser and a dropping funnel in argon atmosphere, and while stirring, 49.5 ml of dehydrated pyridine were added dropwise from the dropping funnel over 1 hour.

After stirring at room temperature for 2 hours, pyridine hydrochloride was removed by filtering and washed with 50 ml of dehydrated ether. Distilling off ether from the filtrate, the remaining solution was stirred at 90° C. for 1.5 hours. The reaction solution was cooled, ether was added, and the solution was washed with 3N-sulfuric acid and then an aqueous solution of sodium hydrogencarbonate. Drying the ether layer with magnesium sulfate and distilling off ether, the remaining solution was vacuum distilled at 7 mmHg, and there was collected 40.1 g (182 mmol) of the fraction distilling at 83° to 89° C. The yield of produced triethoxyethyl acetate was 68.7%.

Taking 4 ml of said triethoxyethyl acetate, 1.00 g (6.19 mmol) of 4-aminoresorcinol hydrochloride and 5.05 mg of sodium hydrogencarbonate, they were introduced into a two-necked flask provided with a cooling condenser under argon atmosphere, and the mixture was stirred with heat at 100° C. for a whole day and night.

The reaction solution was cooled to produce a precipitate which was then filtered. Dissolving the precipitate in acetone, and adding activated carbon, the solution was refluxed with heat for 1.5 hours. Filtering out the activated carbon, the filtrate was run through a silica gel column for concentration. The produced crystal was vacuum dried, and there was obtained 1.07 g (5.17 mmol) of 2-ethoxycarbonyl-6-hydroxybenzoxazole. The yield of the product was 83.5%.

m.p.: 199.5° to 200.2° C.

IR (FIG. 6, KBr, cm⁻¹): 3278, 1736, 1630, 1539, 1489, 1261, 1241, 1145, 116, 849

NMR (FIG. 7, DMSO-d₆): 1.35 (t, 3H), 4.41 (q, 2H), 6.97 (dd, 1H), 7.14 (d, 1H), 7.72 (d, 1H), 10.25 (bs, 1H)

MS (EI): 207 (M⁺) 135

High resolution MS (EI): C₁₀ H₉ O₄ N: Calculated: 207.0591. Observed 207.0561.

EXAMPLE 21 Synthesis of 2-(3-bromophenyl)-6-hydroxybenzoxazole

14.1 ml (107 mmol) of 3-bromobenzoic chloride and 1.7 g (10.5 mmol) of 4-aminoresorcinol hydrochloride were introduced into a three-necked flask provided with a thermometer and a cooling condenser, and the mixture was heated at 90° to 145° C. for 30 minutes. To the residue, an aqueous solution of sodium hydroxide and methanol were added into a homogeneous solution which was then stirred at room temperature for 2 hours. The reaction solution was extracted twice with ethyl acetate and washed with 1N hydrochloric acid then with a saturated sodium chloride solution. Distilling off the excessive ethyl acetate, the obtained precipitate was recrystallized with THF/water. There was obtained 0.68 g (2.35 mmol) of 2-(3-bromophenyl)-6-hydroxybenzoxazole, and the yield was 16.6%.

m.p.: 248.0° to 248.5° C.

IR (FIG. 8, KBr cm⁻¹): 3190, 1630, 1549, 1475, 1325, 1234, 1143, 1062, 835

NMR (FIG. 9, DMSO-d₆): 6.90 (dd, 1H), 7.12 (d, 1H), 7.66 (m, 2H), 7.71 (d, 1H), 8.15 (m, 2H), 9.94 (s, 1H)

MS (EI): 289 (M⁺), 291 (M⁺ +2), 210, 182

High resolution MS (EI): C₁₃ H₈ O₂ NBr: Calculated: 288.9738. Observed 288.9711.

EXAMPLE 22 Synthesis of 2-(2-methylphenyl)-6-hydroxybenzoxazole

14 ml (107.3 mmol) of 2-methylbenzoyl chloride and 1.7 g (10.5 mmol) of 4-aminoresorcinol hydrochloride were introduced into a three-necked flask provided with a thermometer and a cooling condenser, and the mixture was heated at 144° to 215° C. for 1 hour. Removing the excessive acid chloride by distillation, the system was vacuumed to 1 to 1.5 mmHg, and the fraction distilling at 88° to 230° C. was collected. It was 6.2 g.

With ethanol added, the foregoing fraction was recrystallized, and there was obtained 2.32 g (6.76 mmol) of the crystal. To 500 mg (1.46 mmol) of the crystal, 772 mg (13.6 mmol) of KOH, 30 ml of THF, 5 ml of water and 10 ml of methanol were added, and the mixture was stirred at room temperature for a whole day and night. The reaction solution was extracted with ethyl acetate, the extract was washed with saturated sodium chloride solution, and ethyl acetate was distilled off. Upon drying the residue under reduced pressure, there was obtained 320 g of (1.42 mmol) of 2-(2-methylphenyl)-6-hydroxybenzoxazole. The yield was 62.7%.

m.p.: 133.5° to 137.5° C.

IR (FIG. 10, KBr, cm⁻¹): 3064, 1613, 1489, 1224, 1151, 729

NMR (FIG. 11, DMSO-d₆): 2.73 (s, 3H), 6.87 (dd, 1H), 7.11 (d, 1H), 7.42 (m, 3H), 7.64 (d, 1H), 8.06 (m, 1H), 9.86 (s, 1H)

MS (EI): 225 (M⁺), 196, 168, 156, 116, 91, 79, 51, 39

High resolution MS (EI): C₁₄ H₁₁ O₂ N:

Calculated: 225.0790. Observed 225.0764.

EXAMPLE 23 Luminescent assay of peroxidase in use of luminol and 2-ethoxycarbonyl-6-hydroxybenzoxazole

200 μl of a luminol solution (100 mM DMSO solution 10 μl/10ml 0.1 M tris-hydrochloride buffer solution, pH 8.5), 200 μl of the 2-ethoxycarbonyl-6-hydroxybenzoxazole obtained in Example 3 (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution, pH 8.5) 10 μl of a horse radish peroxidase (HRP) solution [10,000 times dilution of 1111 unit/mg with a PBS buffer solution (pH 7.0) containing 1 g/l of BSA], and 10 μl of an aqueous solution of hydrogen peroxide (1000 times dilution of a 9.1 M aqueous solution) were introduced into a plastic cuvette, and the mixture was stirred for 3 seconds with a vortex mixer used, then the luminescent intensity after 1 minute was measured.

Next, 10 μl of a PBS buffer solution (pH 7.0) containing no HRP and the foregoing amounts of luminol and 2-ethoxycarbonyl-6-hydroxybenzoxazole were admixed and stirred, and the luminescent intensity after 1 minute was measured. The ratio of the former to the latter is shown, as signal-to-background ratio (NS ratio), in Table 6.

EXAMPLES 24 AND 25

As Examples 24 and 25, the procedure of Example 23 was followed except that isoluminol (Example 24) and N-(4-aminobutyl)-N-ethylisoluminol (abbreviated as ABEI in the following) (Example 25) were used in place of luminol in Example 23, and the luminescent intensities were measured, as shown in Table 6.

EXAMPLE 26

The procedure of Example 23 was followed except that 2-(3-bromophenyl)-6-hydroxybenzoxazole obtained in Example 21 was used in place of 2-ethoxycarbonyl-6-hydroxybenzoxazole in Example 23, and the luminescent intensity was measured, as shown in Table 6.

EXAMPLES 27 AND 28

As Examples 27 and 28, the procedure of Example 26 was followed except that isoluminol (Example 27) and ABEI (Example 28) were used in place of luminol in Example 26, and the luminescent intensities were measured, as shown in Table 6.

EXAMPLE 29

Similarly to Example 23 except that 2-chloromethyl-6-hydroxybenzoxazole obtained in Example 19 was used in place of 2-ethoxycarbonyl-6-hydroxybenzoxazole in Example 23, the luminescent intensity was measured, as shown in Table 6.

EXAMPLES 30 AND 31

As Examples 30 and 31, the luminescent intensities were measured similarly to Example 29 except that isoluminol (Example 30) and ABEI (Example 31) were used in place of luminol in Example 29, as shown in Table 6.

EXAMPLE 32

Similarly to Example 23 except that 2-(2-methylphenyl)-6-hydroxybenzoxazole obtained in Example 22 was used in place of 2-ethoxycarbonyl-6-hydroxybenzoxazole in Example 20, and luminescent intensity was measured, as shown in Table 6.

EXAMPLES 33 AND 34

As Examples 33 and 34, the luminescent intensities were measured similarly to Example 32 except that isoluminol (Example 33) and ABEI (Example 34) were used in place of luminol in Example 32, as shown in Table 6.

REFERENCES 16 TO 18

As References 16 to 18, luminescent intensities were measured similarly to Examples 23 to 25 except that 2-ethoxycarbonyl-6-hydroxybenzoxazole was not used, as shown in Table 6.

                                      TABLE 6                                      __________________________________________________________________________     Signal-to-background ratios (SN ratios) through combination of                 2,3-dihydro-1,4-phthalazinedione (DPD) with enhancers                                                       Luminescent intensity after                                                    1 minute (relative value)                                Enhancer        DPD   +HRP  -HRP                                                                               SN ratio                                __________________________________________________________________________     Example 23                                                                            2-Ethoxycarbonyl-6-                                                                            Luminol                                                                              798373                                                                               86  9283.4                                         hydroxybenzoxazole                                                      Example 24                                                                            2-Ethoxycarbonyl-6-                                                                            Isoluminol                                                                            40492                                                                               28  1446.1                                         hydroxybenzoxazole                                                      Example 25                                                                            2-Ethoxycarbonyl-6-                                                                            ABEI  114290                                                                               32  3571.6                                         hydroxybenzoxazole                                                      Example 26                                                                            2-(3-Bromophenyl)-6-                                                                           Luminol                                                                               47370*                                                                              246  192.6                                         hydroxybenzoxazole                                                      Example 27                                                                            2-(3-Bromophenyl)-6-                                                                           Isoluminol                                                                           602566                                                                               104 5793.9                                         hydroxybenzoxazole                                                      Example 28                                                                            2-(3-Bromophenyl)-6-                                                                           ABEI  780934                                                                               131 5961.3                                         hydroxybenzoxazole                                                      Example 29                                                                            2-Chloromethyl-6-                                                                              Luminol                                                                              360133                                                                               77  4677.1                                         hydroxybenzoxazole                                                      Example 30                                                                            2-Chloromethyl-6-                                                                              Isoluminol                                                                            5842 30   194.7                                         hydroxybenzoxazole                                                      Example 31                                                                            2-Chloromethyl-6-                                                                              ABEI   15880                                                                               32   496.3                                         hydroxybenzoxazole                                                      Example 32                                                                            2-(2-Methylphenyl)-6-                                                                          Luminol                                                                              1938090*                                                                             78  24847.3                                        hydroxybenzoxazole                                                      Example 33                                                                            2-(2-Methylphenyl)-6-                                                                          Isoluminol                                                                            33186                                                                               49   677.3                                         hydroxybenzoxazole                                                      Example 34                                                                            2-(2-Methylphenyl)-6-                                                                          ABEI   56238                                                                               48  1171.6                                         hydroxybenzoxazole                                                      Reference 16                                                                          None            Luminol                                                                                867 461   1.9                                   Reference 17                                                                          None            Isoluminol                                                                             694 122   5.7                                   Reference 18                                                                          None            ABEI    344 167   1.2                                   __________________________________________________________________________      *10 times value of the luminescent intensity obtained by 10 times dilutio      of HRP.                                                                  

EXAMPLE 35 Synthesis of 2-(3-chlorophenyl)-6-hydroxybenzoxazole

4.5 ml (35.2 mmol) of 3-chlorobenzoyl chloride and 1.0 g (6.19 mmol) of 4-aminoresorcinol hydrochloride were introduced into a three-necked flask provided with a thermometer and a cooling condenser, and the mixture was heated at 170° to 235° C. for 1 hour, then the excessive acid chloride was removed by distillation. To the residue, 1.5 g (38.5 mmol) of NaOH, 20 ml of THF, 20 ml of water and 10 ml of ethanol were added, and the mixture was stirred at room temperature for about 2 hours. The reaction solution was extracted with ethyl acetate, the extract was washed with saturated sodium chloride water solution, and ethyl acetate was distilled off. Recrystallizing the residue with water/methanol/THF and drying the crystal, there was obtained 250 mg (1.02 mmol) of 2-(3-chlorophenyl)-6-hydroxybenzoxazole. The yield was 16.5%.

m.p.: 246.0° to 247.5° C.

IR (FIG. 12, KBr, cm⁻¹): 3146, 1630, 1599, 1551, 1477, 1328, 1232, 1145, 1062, 835

NMR (FIG. 13, DMSO-d₆): 6.90 (dd, 1H), 7.12 (d, 1H), 7.61 (m, 3H), 8.06 (m, 2H), 9.94 (s, 1H)

MS (EI): 245 (M⁺), 247 (M++2), 138, 122, 80, 52

High resolution MS (EI): C₁₃ H₈ O₂ NCl: Calculated: 245.0193. Observed 245.0218.

EXAMPLE 36 Synthesis of 2-(4-chlorophenyl)-6-hydroxybenzoxazole

25 g (142.8 mmol) of 4-chlorobenzoyl chloride and 3.0 g (18.6 mmol) of 4-aminoresorcinol hydrochloride were introduced into a three-necked flask provided with a thermometer and a cooling condenser, and the mixture was heated at 170° to 200° C. for 1 hour, then the excessive acid chloride was removed by distillation. To the residue, 8.4 g (210 mmol) of NaOH, 60 ml of THF, 60 ml of water and 30 ml of methanol were added, and the mixture was stirred at room temperature for about 2 hours. The reaction solution was extracted with ethyl acetate, the extract was washed with saturated sodium chloride water solution, and ethyl acetate was distilled off. Recrystallizing the residue with water/methanol/THF and drying the crystal, there was obtained 1.24 g (5.05 mmol) of 2-(4-chlorophenyl)-6-hydroxybenzoxazole. The yield was 27.2%.

m.p.: 272.8° to 273.5° C.

IR (FIG. 14, KBr, cm⁻¹): 3138, 1632, 1618, 1485, 1236, 1143, 832

NMR (FIG. 15, DMSO-d₆): 6.87 (dd, 1H), 7.11 (d, 1H), 7.62 (m, 3H), 8.13 (d, 2H), 9.90 (s, 1H)

MS(EI): 245 (M⁺), 247 (M⁺ +2), 138, 122

High resolution MS (EI): C₁₃ H₈ O₂ NCl: Calculated 245.0178. Observed 245.0211.

EXAMPLE 37 Synthesis of 2-(2-naphthyl)-6-hydroxybenzoxazole

20 g (104.9 mmol) of 2-naphthyl chloride and 2.5 g (15.5 mmol) of 4-aminoresorcinol hydrochloride were introduced into a three-necked flask provided with a thermometer and a cooling condenser, and the mixture was heated at 135° to 205° C. for 1 hour, then excessive acid chloride was removed by distillation. To the residue, 8.3 g (207.5 mmol) of NaOH, 60 ml of THF, 60 ml of water and 30 ml of methanol were added, and the mixture was stirred at room temperature for about 2 hours. The reaction solution was extracted with ethyl acetate, the extract was washed with saturated sodium chloride water solution, and ethyl acetate was distilled off. Recrystallizing the residue with water/methanol/THF and drying the crystal, there was obtained 1.92 mg (7.36 mmol) of 2-(2-naphthyl)-6-hydroxybenzoxazole. The yield was 47.5%.

m.p.: 226.0° to 226.2° C.

IR (FIG. 16, KBr, cm⁻¹): 3050, 1620, 1485, 1450, 1303, 1141, 1116, 816, 752

NMR (FIG. 17, DMSO-d₆): 6.92 (dd, 1H), 7.17 (d, 1H), 7.64 (m, 3H), 8.08 (m, 4H), 8.74 (s, 1H), 9.92 (s, 1H)

MS (EI): 261 (M⁺), 130

High resolution MS (EI): C₁₇ H₁₁ O₂ N: Calculated: 261.0825. Observed 261.0807.

EXAMPLE 38 Synthesis of 2-(2,4-dichlorophenyl)-6-hydroxybenzoxazole

9.9 ml (70.5 mmol) of 2,4-dichlorobenzoyl chloride and 2.0 g (12.4 mmol) of 4-aminoresorcinol hydrochloride were introduced into a three-necked flask provided with a thermometer and a cooling condenser, and the mixture was heated at 172° to 247° C. for 1 hour, then excessive acid chloride was removed by distillation. To the residue, 6.47 g (161.8 mmol) of NaOH, 60 ml of THF, 60 μl of water and 30 ml of methanol were added, and the mixture was stirred at room temperature for about 2 hours. The reaction solution was extracted with ethyl acetate, the extract was washed with saturated sodium chloride water solution, and ethyl acetate was distilled off. Recrystallizing the residue with water/methanol/THF and drying the crystal, there was obtained 915 mg (3.27 mmol) of 2-(2,4-dichlorophenyl)-6-hydroxybenzoxazole. The yield was 26.3%.

m.p.: 212.5° to 212.8° C.

IR (FIG. 18, KBr, cm⁻¹): 3150, 1638, 1611, 1564, 1489, 1464, 1325, 1232, 1094, 822, 808

NMR (FIG. 19, DMSO-d₆): 6.92 (dd, 1H), 7.11 (d, 1H), 7.66 (m, 2H), 7.85 (dd, 1H), 8.12 (d, 1H), 9.97 (s, 1H)

MS (EI): 279 (M⁺), 281 (M⁺ +2), 283 (M⁺ +4), 172, 139, 108, 80, 52

(EI): C

High resolution MS (EI): C₁₃ H₇ O₂ HCl: Calculated: 278.9898. Observed 278.9876.

EXAMPLE 39 Luminescent assay of peroxidase in use of luminol and 2-(3-chlorophenyl)-6-hydroxybenzoxazole

200 μl of a luminol solution (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution, pH 8.5), 200 μl of the 2-(3-chlorophenyl)-6-hydroxybenzoxazole solution obtained in Example 35 (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution pH 8.5), 10 μl of a horse radish peroxidase (HRP) solution [10,000 times dilution of 1111 unit/mg with a PBS buffer solution (pH 7.0) containing 1 g/l of BSA] and 10 μl of a solution of hydrogen peroxide (1000 times dilution of a 9.1 M aqueous solution) were introduced into a plastic cuvette, and after stirring for 3 seconds with a vortex mixer, the luminescent intensity after 1 minute was measured.

Next, 10 μl of a PBS buffer solution (pH 7.0) not containing HRP and the foregoing amounts of luminol and -(3-chlorophenyl)-6-hydroxybenzoxazole were admixed and stirred, and the luminescent intensity after 1 minute was measured. The ratio of the former to the latter is shown, as signal-to-background ratio (SN ratio), in Table 7.

EXAMPLES 40 AND 41

As Examples 40 and 41, luminescent intensities were measured similarly to Example 39 except that in place of luminol in Example 39, isoluminol (Example 40) and N-(4-aminobutyl)-N-ethylisoluminol (Example 41) were used, as shown in Table 7.

EXAMPLE 42 Luminescent assay of peroxidase in use of luminol and 2-(4-chlorophenyl)-6-hydroxybenzoxazole

200 μl of a luminol solution (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution pH 8.5 , 200 μl of the 2-(4-chlorophenyl)-6-hydroxybenzoxazole solution obtained in Example 36 (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution pH 8.5), 10 μl of a horse radish peroxidase (HRP) solution [10,000 times dilution of 1111 unit/g with a PBS buffer solution (pH 7.0) containing 1 g/l of BSA] and 10 μl of a solution of hydrogen peroxide (1000 times dilution of a 9.1 M aqueous solution) were introduced into a plastic cuvette, and after stirring for 3 seconds with a vortex mixer, the luminescent intensity after 1 minute was measured.

Next, 10 μl of a PBS buffer solution (pH 7.0) not containing HRP and the foregoing amount of luminol and 2-(4-chlorophenyl)-6-hydroxybenzoxazole were mixed and stirred, and the luminescent intensity after 1 minute was measured. The ratio of the former to the latter is shown, as signal-to-background ratio (SN ratio), in Table 7.

EXAMPLES 43 AND 44

As Examples 43 and 44, luminescent intensities were measured similarly to Example 42 except that in place of luminol in Example 42, isoluminol (Example 43) and N-(4-aminobutyl)-N-ethylisoluminol (ABEI) (Example 44) were used, as shown in Table 7.

EXAMPLE 45 Luminescent assay of peroxidase in use of luminol and 2-(2-naphthyl)-6-hydroxybenzoxazole

200 μl of a luminol solution (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution pH 8.5), 200 μl of the 2-(2-naphthyl)-6-hydroxybenzoxazole solution obtained in Example 37 (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution pH 8.5), 10 μl of a horse radish peroxidase (HRP) solution [10,000 times dilution of 1111 unit/mg with a PBS buffer

solution (pH 7.0) containing 1 g/l of BSA] and 10 μl of a solution of hydrogen peroxide (1000 times dilution of a 9.1 M aqueous solution) were introduced into a plastic cuvette, and after stirring for 3 seconds with a vortex mixer, the luminescent intensity after 1 minute was measured.

Next, 10 μl of a PBS buffer solution (pH 7.0) not containing HRP and the foregoing amounts of luminol and 2-(2-naphthyl)-6-hydroxybenzoxazole were admixed and stirred, and the luminescent intensity after 1 minute was measured. The ratio of the former to the latter is shown, as signal-to-background ratio (SN ratio), in Table 7.

EXAMPLES 46 AND 47

As Examples 46 and 47, luminescent intensities were measured similarly to Example 45 except that in place of luminol in Example 45, isoluminol (Example 46) and N-(4-aminobutyl)-N-ethylisoluminol (Example 47) were used, as shown in Table 7.

EXAMPLE 48 Luminescent assay of peroxidase in use of luminol and 2-(2,4-dichlorophenyl)-6-hydroxybenzoxazole

200 μl of a luminol solution (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution pH 8.5), 200 μl of the 2-(2,4-dichlorophenyl)-6-hydroxybenzoxazole solution obtained in Example 38 (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution pH 8.5), 10 μl of a horse radish peroxidase (HRP) solution [10,000 times dilution of 1111 unit/g with a PBS buffer solution (pH 7.0) containing 1 g/l of BSA] and 10 μl of a solution of hydrogen peroxide (1000 times dilution of a 9.1 M aqueous solution) were introduced into a plastic cuvette, and after stirring for 3 seconds with a vortex mixer used, the luminescent intensity after 1 minute was measured.

Next, 10 μl of a PBS buffer solution (pH 7.0) not containing HRP and the foregoing amounts of luminol and 2-(2,4-dichlorophenyl)-6-hydroxybenzoxazole were mixed and stirred, and the luminescent intensity after 1 minute was measured. The ratio of the former to the latter is shown, as signal-to-background ratio (SN ratio), in Table 7.

EXAMPLES 49 AND 50

As Examples 49 and 50, luminescent intensities were measured similarly to Example 48 except that in place of luminol in Example 48, isoluminol (Example 49) and N-(4-aminobutyl)-N-ethylisoluminol (ABEI) (Example 50) were used, as shown in Table 7.

REFERENCES 19 to 21

As References 19 to 21, luminescent intensities were measured quite similarly to Examples 39 to 41 except that 2-(3-chlorophenyl)-6-hydroxybenzoxazole was not used, as shown in Table 7.

                                      TABLE 7                                      __________________________________________________________________________     Signal-to-background ratios (SN ratios) through combination of                 2,3-dihydro-1,4-phthalizinedione (DPD) with enhancers                                                   Luminescent intensity after                                                    1 minute (relative value)                                    Enhancer   DPD    +HRP   -HRP                                                                               SN ratio                                   __________________________________________________________________________     Example 39                                                                            2-(3-Chlorophenyl)-6-                                                                     Luminol                                                                               10253700*                                                                             246 41681.7                                           hydroxybenzoxazole                                                      Example 40                                                                            2-(3-Chlorophenyl)-6-                                                                     Isoluminol                                                                             802093                                                                                85  9436.4                                           hydroxybenzoxazole                                                      Example 41                                                                            2-(3-Chlorophenyl)-6-                                                                     ABEI    1570750*                                                                             100 15707.5                                           hydroxybenzoxazole                                                      Example 42                                                                            2-(4-Chlorophenyl)-6-                                                                     Luminol                                                                                20805800**                                                                           374 55630.5                                           hydroxybenzoxazole                                                      Example 43                                                                            2-(4-Chlorophenyl)-6-                                                                     Isoluminol                                                                             582270                                                                                94 6194.4                                            hydroxybenzoxazole                                                      Example 44                                                                            2-(4-Chlorophenyl)-6-                                                                     ABEI    796149                                                                                96 8293.2                                            hydroxybenzoxazole                                                      Example 45                                                                            2-(2-Naphthyl)-6-                                                                         Luminol                                                                               6168950                                                                               350 17625.6                                           hydroxybenzoxazole                                                      Example 46                                                                            2-(2-Naphthyl)-6-                                                                         Isoluminol                                                                            446699 106 4214.1                                            hydroxybenzoxazole                                                      Example 47                                                                            2-(2-Naphthyl)-6-                                                                         ABEI   591743 115 5145.6                                            hydroxybenzoxazole                                                      Example 48                                                                            2-(2,4-Dichloro)-6-                                                                       Luminol                                                                                2923520**                                                                            129 22662.9                                           hydroxybenzoxazole                                                      Example 49                                                                            2-(2,4-Dichloro)-6-                                                                       Isoluminol                                                                            706751  62 11399.2                                           hydroxybenzoxazole                                                      Example 50                                                                            2-(2,4-Dichloro)-6-                                                                       ABEI   935112  68 13751.6                                           hydroxybenzoxazole                                                      Reference 19                                                                          None       Luminol                                                                                 583  377 1.5                                               hydroxybenzoxazole                                                      Reference 20                                                                          None       Isoluminol                                                                              463  160 2.9                                        Reference 21                                                                          None       ABEI     273  174 1.6                                        __________________________________________________________________________      *10 times value of the luminescent intensity obtained through 10 times         dilution of HRP.                                                               **20 times value of the luminescent intensity obtained through 20 times        dilution of HRP.                                                         

EXAMPLE 51 Luminescent assay of CA15-3 antigen in use of 2-ethoxycarbonyl-6-hydroxybenzoxazole

Diluting a CA15-3 antigen solution (615 U/ml) with a phosphate buffer solution (PBS) containing 0.25% bovine serum albumin into solutions of the concentrations of 300 U/ml, 200 U/ml, 100 U/ml, 50 U/ml, 25 U/ml and 0 U/ml (PBS containing 0.25 bovine serum albumin), these were taken as standard CA15-3 solutions.

The standard CA15-3 solutions of the foregoing concentrations were introduced to the wells of a tray (25 wells), each in 200 μl. Then, 300 μl of a peroxidase labeled anti-CA15-3 antibody (mouse) was added to the respective wells. To each well, an antibody coated bead, having the adhering liquid soaked up with filter paper, was added with a pincette.

Applying a tray cover seal, the tray was lightly tapped to mix the components in the respective wells, and each mixture was allowed to react at 25° C. for 2 hours. After completion of the reaction, the beads were washed 3 times, each time with 5 ml of physiological saline, with a bead washer used. After washing, each bead in the tray was transferred to a test tube then to a plastic cuvette for measurement with a luminometer.

100 μl of a luminol Na salt solution (18 times dilution of a solution of 12.6 mM, luminol Na salt/0.1 M tris-hydrochloride buffer solution pH 8.5 with the same buffer solution), 100 μl of a 2-ethoxycarbonyl-6-hydroxybenzoxazole solution (100 mM DMSO solution 10 μl/10 ml, 0.1 M tris-hydrochloride buffer solution pH 8.5) and 100 μl of a solution of hydrogen peroxide (18 times dilution of 16.2 μM hydrogen peroxide/0.01 M disodium hydrogen phosphate-citric acid buffer solution pH 5.2 with the same buffer solution) were added to a plastic vial, and after heating at 37° C. for 10 minutes, the luminescence was measured for 60 seconds. 1/6 Values of the cumulative values of luminescent intensities of from 50 seconds to 60 seconds are shown in Table 8.

Then, the ratios of the 1/6 values of the cumulative values of luminescent intensities of from 50 seconds to 60 seconds of the standard CA15-3 solutions (300 U/ml, 200 U/ml, 100 U/ml, 50 U/ml and 25 U/ml) to the 1/6 value of the cumulative value of luminescent intensity of from 50 seconds to 60 seconds of 0 U/ml (SN ratios) were obtained, as shown in Table 8 and FIG. 20.

Reference 22

According to the procedure of Example 35 except that 2-ethoxycarbonyl-6-hydroxybenzoxazole was not used, the luminescent intensities and SN ratios were obtained, as shown in Table 8 and FIG. 20.

                                      TABLE 8                                      __________________________________________________________________________     Analysis of CA15-3; 1/6 Values of the cumulative values of                     luminescent intensities of from 50 seconds to 60 seconds                                                CA15-3 (U/ml)                                                Enhancer          0  25  50 100 200 300                                 __________________________________________________________________________     Example 51                                                                            2-Ethoxycarbonyl-                                                                        Luminescent                                                                            151                                                                               763 2729                                                                              18333                                                                              54503                                                                              94172                                      6-hydroxy intensity                                                            benzoxazole                                                                              (relative value)                                                               SN ratio                                                                                1 4.86                                                                               17.4                                                                               117                                                                                347                                                                                600                                Reference 22                                                                          None      Luminescent                                                                            250                                                                               329  397                                                                               968                                                                                1422                                                                               8625                                                intensity                                                                      (relative value)                                                               SN ratio                                                                                1 1.32                                                                               1.59                                                                              3.87                                                                               5.69                                                                               34.5                                __________________________________________________________________________

As described in the foregoing, the method of luminescence analysis of the present invention enables high sensitivity and prompt determination of substances. 

We claim:
 1. A process for detecting or determining the presence of a substance by the chemiluminescence produced through reaction of (a) peroxidase or a derivative thereof, (b) an oxidant and (c) luminol or isoluminol or a derivative thereof, wherein said chemiluminescence-inducing reaction is carried out in the presence of at least one compound selected from the group consisting of 2-hydroxy-9-fluorenone, the compound ##STR11## and oxazole derivatives of the formula ##STR12## wherein R₁ represents hydrogen, C_(n) H_(2n+1), XC_(n) H_(2n), C_(n) H_(2n+1) CO₂, a phenyl group, a naphthyl group, C_(n) H_(2n+1) C₆ H₄, YC₆ H₄, or XYC₆ H₃ ; wherein n is a positive integer from 1 to 4, X is F, Cl, Br, or I, and Y is F, Cl, Br, I, or a phenyl group.
 2. The process according to claim 1, wherein R₁ is selected from the group consisting of fluoromethyl, 1-chloromethyl, bromomethyl, iodomethyl, 1-fluoromethyl, 2-fluoromethyl, 1-chloroethyl, 2-chloroethyl, 1-bromoethyl, 2-bromoethyl, 1-iodoethyl, 2-iodoethyl, 1-fluoropropyl, 2-fluoropropyl, 3-fluoropropyl, 1-fluoro-1-methylethyl, 2-fluoro-1-methylethyl, 1-chloropropyl, 2-chloropropyl, 3-chloropropyl, 1-chloro-1-methylethyl, 2-chloro-1-methylethyl, 1-bromopropyl, 2-bromopropyl, 3-bromopropyl, 1-bromo-1-methylethyl, 2-bromo-1-methylethyl, 1-iodopropyl, 2-iodopropyl, 3-iodopropyl, 1-iodo-1-methylethyl, 2-iodo-1-methylethyl, 1-fluorobutyl, 2-fluorobutyl, 3-fluorobutyl, 4-fluorobutyl, 1-fluoro-1-methylpropyl, 2-fluoro-1-methylpropyl, 3-fluoro-1-methylpropyl, 1-fluoromethylpropyl, 1-fluoro-2-methylpropyl, 2-fluoro-2-methylpropyl, 3-fluoro-2-methylpropyl, 1-fluoromethyl-1,1-dimethylmethyl, 1-chlorobutyl, 2-chlorobutyl, 3-chlorobutyl, 4-chlorobutyl, 1-chloro-1-methylpropyl, 2-chloro-1-methylpropyl, 3-chloro-1-methylpropyl, 1-chloromethylpropyl, chloro-2-methylpropyl, 2-chloro-2-methylpropyl, 3-chloro-2-methylpropyl, 1-chloromethyl-1,1-dimethylmethyl, 1-bromobutyl, 2-bromobutyl, 3-bromobutyl, 4-bromobutyl, 1-bromo-1methylpropyl, 2-bromo-1-methylpropyl, 3-bromo-1-methylpropyl, 1-bromomethylpropyl, 1-bromo-2methylpropyl, 2-bromo-2-methylpropyl, 3-bromo-2-methylpropyl, 1-bromomethylmethyl-1,1-dimethylmethyl, 1-iodobutyl, 2-iodobutyl, 3-iodobutyl, 4-iodobutyl, 1-iodo-1-methylpropyl, 2-iodo-1-methylpropyl, 3-iodo-1methylpropyl, 1-iodo-2-methylpropyl, 2-iodo-2-methylpropyl, 3-iodo-2-methylpropyl and 1-iodomethyl-1,1-dimethylmethyl.
 3. The process according to claim 1, wherein R₁ is selected from the group consisting of methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, 1-methylethoxycarbonyl, butoxycarbonyl, 1-methylpropoxycarbonyl, 2-methylpropoxycarbonyl and 1,1-dimethylethoxycarbonyl.
 4. The process according to claim 1, wherein R₁ is selected from the group consisting of 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 2-propylphenyl, 3-propylphenyl, 4-propylphenyl, 2-(1-methylphenyl), 3-(1-methylethyl), 4-(1methylethyl), 2-butylphenyl, 3-butylphenyl, 4-butylphenyl, 2-(1-methylpropyl)phenyl, 3-(1-methylpropyl)phenyl, 4-(1-methylpropyl)phenyl, 2-(2-methylpropyl)phenyl, 3-(2-methylpropyl)phenyl, 4-(2-methylpropyl)phenyl, 2-(1,1-dimethylethyl)phenyl, 3-(1,1-dimethylethyl)phenyl and 4-(1,1-dimethylethyl)phenyl.
 5. The process according to claim 1, wherein R₁ is selected from the group consisting of 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 2-bromophenyl, 3-bromophenyl, 4-bromophenyl, 2-iodophenyl, 3-iodophenyl and 4-iodophenyl.
 6. The process according to claim 1, wherein R₁ is selected from the group consisting of 2,4-dichlorophenyl and 3,5-dichlorophenyl.
 7. The process according to claim 1, wherein R₁ is selected from the group consisting of hydrogen, a methyl group, a chloromethyl group, an ethoxycarbonyl group, a phenyl group, a bromophenyl group, a methylphenyl group, a chlorophenyl group, a naphthyl group and a dichlorophenyl group.
 8. An oxazole derivative having the formula ##STR13## wherein R₂ is selected from the group consisting of XC_(n) H_(2n), C_(n) H_(2n+1) CO₂, a naphthyl group, C_(n) H_(2n+1) C₆ H₄, Y₆ H₄ and XYC₆ H₃, wherein n is a positive integer of 1 to 4, X is F, Cl, Br, or I, and Y is F, Cl, Br, I, or a phenyl group.
 9. The oxazole derivative according to claim 8, wherein R₂ is selected from the group consisting of fluoromethyl, 1-chloromethyl, bromomethyl, iodomethyl, 1-fluoromethyl, 2-fluoromethyl, 1-chloroethyl, 2-chloroethyl, 1-bromoethyl, 2-bromoethyl, 1-iodoethyl, 2-iodoethyl, 1-fluoropropyl, 2-fluoropropyl, 3-fluoropropyl, 1-fluoro-1-methylethyl, 2-fluoro-1-methylethyl, 1-chloropropyl, 2-chloropropyl, 3-chloropropyl, 1-chloro-1-methylethyl, 2-chloro-1-methylethyl, 1-bromopropyl, 2-bromopropyl, 3-bromopropyl, 1-bromo-1-methylethyl, 2-bromo-1-methylethyl, 1-iodopropyl, 2-iodopropyl, 3-iodopropyl, 1-iodo-1-methylethyl, 2-iodo-1-methylethyl, 1-fluorobutyl, 2-fluorobutyl, 3-fluorobutyl, 4-fluorobutyl, 1-fluoro-1-methylpropyl, 2-fluoro-1-methylpropyl, 3-fluoro-1-methylpropyl, 1-fluoromethylpropyl, 1-fluoro-2-methylpropyl, 2-fluoro-2-methylpropyl, 3-fluoro-2-methylpropyl, 1-fluoromethyl-1,1-dimethylmethyl, 1-chlorobutyl, 2-chlorobutyl, 3-chlorobutyl, 4-chlorobutyl, 1-chloro-1-methylpropyl, 2-chloro-1-methylpropyl, 3-chloro-1-methylpropyl, 1-chloromethylpropyl, 1-chloro-2-methylpropyl, 2-chloro-2-methylpropyl, 3-chloro-2-methylpropyl, 1-chloromethyl-1,1-dimethylmethyl, 1-bromobutyl, 2-bromobutyl, 3-bromobutyl, 4-bromobutyl, 1-bromo-1methylpropyl, 2-bromo-1-methylpropyl, 3-bromo-1-methylpropyl, 1-bromomethylpropyl, 1-bromo-2methylpropyl, 2-bromo-2-methylpropyl, 3-bromo-2-methylpropyl, 1-bromomethylmethyl-1,1-dimethylmethyl, 1-iodobutyl, 2-iodobutyl, 3-iodobutyl, 4-iodobutyl, 1-iodo-1-methylpropyl, 2-iodo-1-methylpropyl, 3-iodo-1methylpropyl, 1-iodo-2-methylpropyl, 2-iodo-2-methylpropyl, 3-iodo-2-methylpropyl and 1-iodomethyl-1,1-dimethylmethyl.
 10. The oxazole derivative according to claim 8, wherein R₁ is selected from the group consisting of methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, 1-methylethoxycarbonyl, butoxycarbonyl, 1-methylpropoxycarbonyl, 2-methylpropoxycarbonyl and 1,1-dimethyl-ethoxycarbonyl.
 11. The oxazole derivative according to claim 8, wherein R₁ is selected from the group consisting of 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 2-propylphenyl, 3-propylphenyl, 4-propylphenyl, 2-(1-methylethyl), 3-(1-methylethyl), 4-(1-methylethyl), 2-butylphenyl, 3-butylphenyl, 4-butylphenyl, 2-(1-methylpropyl)phenyl, 3-(1-methylpropyl)phenyl, 4-(1-methylpropyl)phenyl, 2-(2-methylpropyl)phenyl, 3-(2-methylpropyl)phenyl, 4-(2-methylpropyl)phenyl, 2-(1,1-dimethylethyl)phenyl, 3-(1,1-dimethylethyl)phenyl and 4-(1,1-dimethylethyl)phenyl.
 12. The oxazole derivative according to claim 8, wherein R₁ is selected from the group consisting of 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 2-bromophenyl, 3-bromophenyl, 4-bromophenyl, 2-iodophenyl, 3-iodophenyl and 4-iodophenyl.
 13. The oxazole derivative according to claim 8, wherein R₁ is selected from the group consisting of 2,4-dichlorophenyl and 3,5-dichlorophenyl.
 14. The oxazole derivative according to claim 8, wherein R₂ is selected from the group consisting of a chloromethyl group, an ethoxycarbonyl group, a bromophenyl group, a chlorophenyl group, a naphthyl group, a dichlorophenyl group and a methylphenyl group. 